IN-VITRO MICROLEAKAGE OF ETCHED AND REBONDED CLASS-5 COMPOSITE RESIN RESTORATIONS

The purpose of this study was to measure the effect rebonding, with an d without etching restoration margins, had on the microleakage of clas s 5 composite restorations, Eighty-two class 5 composite restorations were placed in extracted human molars with one margin on etched enamel and one below the cementoenamel junction. After finishing with disks, the teeth were divided into seven margin treatment groups: 1) restora tions with no rebonding (control), 2) restoration margins rebonded wit h Universal Bond 3 primer, 3) restoration margins etched with 37% phos phoric acid and rebonded with Universal Bond 3 primer, 4) restoration margins rebonded with Universal Bond 3 adhesive, 5) restoration margin s etched and rebonded with Universal Bond 3 adhesive, 6) restoration m argins rebonded with Fortify, and 7) restoration margins etched and re bonded with Fortify. After storage in a chlorine-based disinfectant fo r 1 week, the restorations were thermocycled and then soaked in dye, A fter sectioning, microleakage was assessed by measuring the extent of dye penetration along the restoration-tooth interface, At the enamel m argins there was no statistical difference in microleakage rebonded wi th or without etching. On the gingival margins there was a statistical ly significant reduction in microleakage for the nonetched Universal B ond 3 adhesive rebonded group compared to the nonrebonded control.